Given the frequent occurrence of accidents in which the driver's ability was impaired by drugs, the issue of how drugs of abuse affect brain function during driving and other potentially dangerous activities is a major public health concern. This project aims to develop an enabling technology that will accelerate research in this area. It will build on recent progress in monitoring brain function of people working at computers to develop a highly-automated affordable system for studying the effects of drugs of abuse on brain mechanisms mediating complex task performance. The system will embody accumulated expertise about the analysis of EEC signals into automated software that will vastly reduce the labor and knowledge required to extract useful information from them, enabling scientists conducting drug abuse research who may lack specific expertise in quantitative neurophysiology to successfully record and analyze EEC signals from research subjects operating driving simulators or performing other naturalistic tasks. The Phase I project will determine the feasibility of this concept in the context of marijuana-intoxicated subjects operating an automobile driving simulator. If the project reaches Phase II, the system would be fully implemented and tested with other drugs of abuse, alone and in combination. The proposed system would enable the first cost-effective large-scale research studies of how drugs affect neural signals related to focusing and maintaining attention during performance of complex tasks such as driving. Because the same underlying technology could be used in clinical trials to evaluate drug side-effects that might impair cognitive abilities, there is likely to be a significant market for such technology. [unreadable] [unreadable]